A. Technical Field
The present invention pertains generally to image processing, and relates more particularly to systems and methods for unwarping or removing the distortion from a scanned image.
B. Background of the Invention
When a copy of a document is desired, a photocopier or scanner is typically used to duplicate the document. The photocopier, scanner, or other such apparatus with image capturing capabilities generates an image of the document. The image may comprise an array of pixels, wherein each pixel has a location within the image and a color value. When taken together in their proper position within the array, the pixels form the image.
A measure of the quality of the image is the degree to which it is an accurate copy of the document. Problems or circumstances may result in the creation of an image that is a distorted version of the document.
A common situation that results in a distorted image occurs when the page of a bound volume is copied, particularly when copied using flatbed scanning. Because the binding of the volume restricts the physical layout of the book, it is not always possible to place the entire page of the bound volume against the scanning surface. The portion of the page proximate to the binding or spine curves away from the scanning surface and may result in an image with distortions.
Often, the content of the page undergoes three major sources of degradation or distortion. First, the portion of the page running along the spine of the volume typically appears shaded. Second, lines, such as lines of text, appear curved because of the curvature of the volume. And third, in some cases, the document may be misaligned with the image capturing device resulting in an image that is tilted or skewed.
It is typically preferred that the image has as few distortions as possible. Thus, it would be beneficial to remove the shading that exists along the spine and to straighten the content. Accordingly, what is needed are systems and methods to remove or reduce the distortion in an image.